Pregnancy Rating

FDA Pregnancy Category

Initially developed in 1979 by US FDA to guide providers in interpretation of teratogenic risk associated with medications

• Category A:

Adequate, well-controlled human studies have not shown increased risk to the fetus

• Category B:

Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women

• Category C:

Animal reproduction studies have shown an adverse effect on the fetus; there are no adequate and well-controlled studies in humans, and the benefits from the use of the drug in pregnant women may be acceptable despite its potential risks

• Category D:

Well-controlled human studies have demonstrated fetal risk, but the benefit of use may be acceptable despite its potential risks

• Category X:

Studies have demonstrated animal or human fetal abnormalities and the risk of the drug clearly outweighs the potential benefits